These notes for CBSE Class 10 Science, Chapter 8, explain the process of reproduction in organisms. Reproduction is defined as the production of new organisms from existing ones. The chapter details two primary modes: asexual reproduction, which includes methods like binary fission, budding, and vegetative propagation, and sexual reproduction, involving the fusion of male and female gametes to form a zygote through fertilization. It elaborates on sexual reproduction in flowering plants, covering pollination and the development of fruits and seeds. The notes also describe human reproduction, including the male and female reproductive systems, fertilization in the fallopian tube, menstrual flow, menopause, and fertility control methods like barrier, hormonal, chemical, and surgical techniques (vasectomy and tubectomy). Finally, it introduces sexually transmitted diseases (STDs). These notes are designed to aid students in revising the key concepts for their exams.
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1. The production of new organisms from the existing organisms ofthe same species is
known as reproduction.
2. Asexual Reproduction : Modes of sexual reproduction used are binary fission,
multiple fission, Budding, spore formation, regeneration, vegetative propagation, tissue
culture, fragmentation
3. Sexual Reproduction : In sexual reproduction, a male gamete (germ cells) fuses with a
female gamete to form a new cell called ‘zygote’. This zygote then grows and develop into a
new organism in due course of time.
When male gamete and female gamete fuse, they form a zygote and the process is known as
fertilization.
Fertilization is of two types :- External fertilization and Internal fertilization.
4. Sexual Reproduction in Flowering Plants :
Flower is meant essentially for sexual reproduction.
Pollination is the process in which pollen grains are transferred from the anther to stigma
of the carpel. It is of two types self pollination and cross-pollination.
? In the fertilization process primary endospermic nucleus is formed.
? After the fertilization process, ovary developes into the fruit whereas ovules into the
seed.
5. Reproduction in Human Being : The sex organ in males are testes and ova in females.
Male reproductive organ consist of a pair of testes, vasdeferens, a pair of epididymis, a
pair of ejaculatory duct, urethra, pairs of accessory gland.
? Female reproductive part consist of a pair of ovaries, a pair of fallopian tube,
uterus, vagina, external genitalia, mammary glands and accessory glands. Ovary
produces the female gametes (eggs or ova) and female sex hormone (estrogen).
? If sperms are present, fertilization of ovum takes place in the upper end of the
fallopian tube.
? Bleeding accompanied by discharge of soft tissue lining the reproductive tract
is menstrual flow. It last for 3-5 days.
? Secretory phase lasts for 12-14 days.
? Fertilization process occurs in fallopian tube. In this process zygote is formed. In this
process umbilical cord is produced which is attached to foetus. During this
? process two hormones are produced which are estrogen and progesterone.
? Progesterone stops mensturation and prevents ovulation. The placenta protects the body
against diseases. Due to contraction of uterine muscles young one is expelled and the
phenomenon is called parturition.
? If the egg is not fertilized, it lives for about one day. Since the ovary releases one
egg every month, the uterus also prepares it self every month to recieve a fertilized egg.
? After the age of 45-50 years menses stop and process is called menopause.
? Fertility control can be done chemically, mechanically or surgically.
6. Reproductive Health Barrier methods
(i) Mechanical barrier method:- They prevent contraception by preventing either sperms from
entering uterus or preventing implantation if fertilization has occurred.
The instruments are condom, cercival cap, diaphragm & ICDU method.
(ii) Hormonal method: They are used by women for suppressing the production of ovum. i.e. ,
oral pills, Implants morning after pills.
(iii) Chemical contraception: They are creams, jellies and foaming tables which are placed in
vagina for killing the sperms at the time of coitus.
(iv) Surgical techniques:—
(a) Vasectomy: — The two vasa deferential of the male are blocked by cutting a small piece of
tying the rest. This prevents the passage of sperms from testes to semen.
(b) Tubectomy:— A portion of both the fallopian tubes is excised to ligated to block the
passage of ovum
7. Sexually Transmitted Diseases (STDs)
It is a group of infections caused by different types of pathogens that are transmitted by sexual
contact between a healthy person and an infected person. The sexually transmitted diseases are
also called venereal diseases (VDs). Some 30 different types of STDs are known. Fol example :
Gonorrhoea, Syphilis, Trichomonas, Genital warts, AIDS.
Reproduction is the biological process by which new individual organisms, "offspring", are produced from their "parents". In essence, it is the production of new organisms from the existing ones of the same species.
The two main types of reproduction are asexual reproduction, where a single parent produces offspring genetically identical to itself, and sexual reproduction, which involves two parents contributing genetic material to produce offspring that are genetically unique.
Fertilization is the process where a male gamete fuses with a female gamete to form a zygote. It can be external (outside the body) or internal (inside the body).
Pollination is the transfer of pollen grains from the anther to the stigma of a carpel. It can be self-pollination (within the same flower) or cross-pollination (between different flowers).
Fertility control can be achieved through barrier methods (like condoms), hormonal methods (like oral pills), chemical contraception (creams, jellies), and surgical techniques (vasectomy and tubectomy).
STDs are infections transmitted through sexual contact between an infected person and a healthy person. Examples include Gonorrhoea, Syphilis, and AIDS.
Menopause is the cessation of menstruation, typically occurring in women between the ages of 45-50 years, marking the end of their reproductive capability.
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